1. Field of the Invention
The present invention relates generally to computer input devices, and in particular, to a Z-axis module for use in a computer input device.
2. Background Art
Computer input devices, such as mice, track balls, touch pads and others, are not only designed to work with application software and to coordinate X-Y plane movements, but to also provide xe2x80x9cclickxe2x80x9d functions for allowing the user to select onscreen displays. However, in order to scroll a screen, an input device must be pointed to the scrolling bar of the screen display. Therefore, the cursor of the input device must be repeatedly positioned between the working area of the area an the side scrolling bar, which is very inconvenient to the user. Further, to select files or application software that are not currently displayed on the screen, the user must xe2x80x9chidexe2x80x9d the present file and then use the push buttons or keys of the input device to sequentially change the sub-directory with repeated xe2x80x9cdouble-clicksxe2x80x9d. This process can be quite tedious and boring.
To overcome the drawbacks of and to simplify the operations described above, attempts have been made to provide computer input devices with another dimension of input, which has been referred to as xe2x80x9cZ-axisxe2x80x9d control. For example, U.S. Pat. Nos. 5,530,455 and 5,657,051 illustrate how a computer input device cooperates with software to provide improved operation where a screen can be scrolled, or any application software selected, regardless of the location of the cursor.
In many instances, this Z-axis control has been embodied in the form of a wheel-type Z-axis button. For example, FIG. 1 illustrates a conventional multi-dimensional computer mouse 1 having a wheel-type Z-axis button 12 positioned between two selection buttons 11, with a portion of the Z-axis button 12 exposed and protruding from the upper housing of the mouse 1.
Unfortunately, most of the conventional Z-axis devices suffer from several drawbacks. First, these Z-axis devices incorporate many tiny parts and components, thereby making assembly very difficult, often necessitating a variety of manufacturing processes and materials in organizing these parts for assembly.
Second, conventional Z-axis devices usually provide an additional (second) PC board to move with the Z-axis device so as to maintain the alignment between the light-receiving sensors and the notches or grooves of a rotating grating wheel when the Z-axis button is clicked (i.e., pressed to exert a downward force). However, the space and wiring requirements introduced by a second PC board inevitably complicate the design of the Z-axis module, and the assembly of the input device.
Third, conventional Z-axis devices usually have a resilient element that biases the Z-axis button against the downward force. This resilient element is usually installed in a manner in which it is offset from the center of the Z-axis device. This is illustrated in U.S. Pat. No. 5,808,568 (Wu), in which the resilient member or spring 15 is offset from the center of the Z-axis button 13. Therefore, depressing the Z-axis button will result in lateral movement of the resilient element, which hinders the operation of the Z-axis device.
Thus, there remains a need for a Z-axis device that overcomes the disadvantages set forth above, while retaining all functions that can be performed by conventional Z-axis devices.
The objects of the present invention can be accomplished by providing a finger-operated module for use with an input device. The finger-operated module has a base having a plurality of walls coupled to each other to define an interior space, a wheel fitted inside interior space and extending through the housing for manipulation by a user, and a resilient element positioned between the wheel and the base.
In one embodiment of the present invention, the wheel is coupled to the base for vertical reciprocating movement inside the interior space when the base is stationary.
According to another embodiment of the present invention, the resilient element is positioned along an imaginary center line that extends through the center of the resilient element and the center of the wheel.